A disposable apparatus to dispense an amount of liquid from a closed container such as a stoppered blood collection tube. The apparatus comprises a stopper piercing means to access the interior of a closed blood collection tube; a gas passage means to allow a metered amount of gas to be forced into the...http://www.google.ca/patents/US5413246?utm_source=gb-gplus-sharePatent US5413246 - Apparatus and method for aliquotting phases of blood
